--- old/src/hotspot/share/c1/c1_Instruction.hpp	2018-12-03 15:48:56.184379669 -0800
+++ new/src/hotspot/share/c1/c1_Instruction.hpp	2018-12-03 15:48:56.040374169 -0800
@@ -649,12 +649,14 @@
  private:
   int         _pf_flags; // the flags of the phi function
   int         _index;    // to value on operand stack (index < 0) or to local
+  ciType*     _exact_type; // preserve type information for flattened arrays.
  public:
   // creation
-  Phi(ValueType* type, BlockBegin* b, int index)
+  Phi(ValueType* type, BlockBegin* b, int index, ciType* exact_type)
   : Instruction(type->base())
   , _pf_flags(0)
   , _index(index)
+  , _exact_type(exact_type)
   {
     _block = b;
     NOT_PRODUCT(set_printable_bci(Value(b)->printable_bci()));
@@ -663,6 +665,14 @@
     }
   }
 
+  virtual ciType* exact_type() const {
+    return _exact_type;
+  }
+
+  virtual ciType* declared_type() const {
+    return _exact_type;
+  }
+
   // flags
   enum Flag {
     no_flag         = 0,